On-chip integrated plasmon-induced high-performance self-powered Pt/GaN ultraviolet photodetector

The advantages of on-chip integrated photodetectors, such as miniaturization, high integration, and reliability, make them an indispensable and important part of electronic devices and systems. Herein, we experimentally exhibited a monolithically integrated ultraviolet photodetector utilizing GaN microcylinder epitaxial structure on Si wafer, with its photoresponse properties plasmonically boosted using Pt nanoparticles via specific sizes. When illuminated upon ultraviolet light at 0 V bias, the Pt/GaN device exhibits significant photovoltaic performances, including a peak responsivity of 200.1 mA W⁻¹, external quantum efficiency of 65%, and other figures-of-merit. Finite element analysis and energy band theory confirm that the excellent photodetection properties of the Pt/GaN device are related to the strong plasmon absorption and the increase of hot electrons injected into the GaN conduction band, which considerably improves its photoresponse performance and robustness in application. To realize the multipurpose capability of the devices, we validated the application of Pt/GaN as turbidity sensing and achieved a resolution of up to 100 NTU. Moreover, the prepared devices can be used as optical data receivers for optical communication. These findings provide references for on-chip detectors to improve the overall system performance and promote the realization of more complex applications.